THREE men being questioned about the murder of burglar Christopher Warren were all well known to the victim.
The suspects, including one in his 60s, were detained during a series of searches in Dublin.
Warren died after he was shot in what appeared to have been a punishment attack that went wrong on December 28.
Shortly after the shooting, two men were arrested but later released without charge.
One of the latest suspects, a man in his 60s is being detained under section 30 of the Offences Against the State Act and can be held for up to three days. The other two, who are in their 20s, are in custody under section 50 of the 2007 Criminal Justice Act and can be held for up to a week.
Warren was on temporary release from prison at the time.